1. Field of the Invention
The present invention relates to a lubricating device for a motorcycle combustion engine having a lower center of gravity.
2. Description of the Prior Art
The conventional lubricating device for a multicylinder combustion engine generally employed in motorcycles is of a design in which journal oiling passages for supplying a lubricant oil from a main gallery, formed in a lower portion of the engine casing, towards bearings for a crankshaft are so formed as to branch off from the main gallery. Lubrication for a valve mechanism and a transmission is carried out through oil supply passages that are separate from the journal oiling passages. See, for example, the Japanese Laid-open Patent Publication No. 2001-227317.
However, the prior art lubricating device has a problem. Specifically, since the main gallery is formed to extend straight horizontally in a lower portion of the engine casing in a transverse direction, that is, in a left to right direction of the motorcycle, opposite end portions of the lower portion of the engine casing, which correspond to opposite end portions of the main gallery, extend horizontally in the transverse direction, resulting in an insufficient banking angle being secured. The banking angle represents the angle of tilt of the motorcycle with respect to a road surface during, for example, cornering. Because of this, the prior lubricating device has a difficulty in allowing the position of the motorcycle combustion engine to be lowered in an attempt to lower the center of gravity of the motorcycle as a whole.